Effect of Synthesis Routes and Support Nature on Co-Based Catalysts for Low-Temperature Catalytic Combustion of Methane

Catalytic combustion of methane (CH4) is one of the promising methods to tackle the emission of CH4 through natural gas-based vehicles. Herein, to study the impact of different preparation methods and support, a series of monometallic cobalt-based catalysts was prepared to examine the total oxidation of CH4 at low temperatures. With a 20% total metallic loading, the samples were synthesized using two different methods: wet impregnation and coprecipitation, with two different types of support, such as cerium oxide (CeO2) and silica oxide (SiO2). All prepared samples were characterized using several techniques to examine their physicochemical properties, such as XRD, Raman, FTIR, SEM-EDS, XPS, H2-TPR, and O2-TPD, which confirmed the crystalline phases and structural integrity of the catalysts. Structural and surface analyses confirmed that Co incorporation into CeO2 generated oxygen vacancies and stabilized Co3+ with high oxygen mobility and reducibility, whereas SiO2-supported catalysts showed weaker dispersion and limited redox activity. The catalytic performance of all prepared samples was investigated in the temperature range of 250–600 °C, and CeO2-based catalysts synthesized through the wet impregnation method exhibited 91% conversion at 600 °C, which is 25% higher than that of their SiO2-based counterpart due to the formation of oxygen vacancies, which enhanced the catalytic activity. The robustness of the best-performing catalyst was tested by varying the WHSVs to check the performance under real conditions. The findings from this study pave the way for the development of low-temperature catalytic processes for methane oxidation.